THE STUDY OF PHYCOBILIPROTEINS IN Porphyra yezoensis——THE PHYSICAL AND IMMUNO-CHEMICAL PROPERTIES OF R-PHYCOERYTHRIN*

There are two kinds of phycoerythrin of different physical properties in Porphyra yezoensis. Their molecular weights are different. They are both composed of a-subunit and β-subunit. Their polymeric forms are （αβ）n. The absorption bands and fluorescence emission bands of the smaller molecules show hypsochromic shifts of several rims relative to that of the polymeric molecules. The isoelectric point of the former is lower than that of the latter. It is worthy of note that the smaller molecules display binding activities with guinea pig antisera. Through using radioimmunoassay, when the depression of the biuding activity ofI-insulin reaches 50%, the required quantity of the smaller molecules of R-phycoerythrin would be ca. 0.1mg, corresponding to ca. 8μ units of insulin used in a parallel experiment （26 units corresponding to 1 mg of insulin）.